If you always wanted to know how to pin that one package so it won't get upgraded, here's how.
You create a file in /etc/apt/preferences.d, e.g. /etc/apt/preferences.d/xorg
The contents must look like this:

"Package: xorg
Pin: version 5:55ubuntu1
Pin-Priority: 1001"

You get the right version number for Pin: with apt-cache policy. Done! If you like this post, you can share it, check out the related posts section below and subscribe to one of the RSS feeds so you don't miss the next one.